Electric translating circuit



Aug. 2, 1932.

ELECTRIC TRANSLATING CIRCUIT Filed April 17, 19:51

Inventor. D z-n/i d c-pri'nce.

ma/k His Attorneg.

D. c. PRINCE 1,870,022

Patented Aug. 2, 1932 UNITED STATES PATENT OFFICE DAVID C. PRINCE, OFSCHENECTADY, NEW YORK, ASSIGNOB T0 GENERAL ELECTRI COMPANY, ACORPORATION OF NEW YORK ELECTRIC TBANSLATING CIRCUIT Application filedApril 17,

My invention relates to electric translating circuits and moreparticularly to such circuits utilizing electric valves for transmittingenergy from an alternating current supply circuit to a direct oralternating current load circuit. I

Heretofore there have been proposed numerous arrangements utilizingelectric valves for transmitting energy from an alternating currentsupply circuit to a dlrect or alternating current load circuit. The ma-'ority of the arrangements of the prior art ave, however, requiredmanual attent on or adjustment in order to control the amount of energydelivered to the load circuit. In the transmission of energy from analternating current supply circuit to a load circuit the use of electricvalves of the vapor electric discharge type has been found particularlyadvantageous because 'of the relatively large amounts of power which'maybe handled at ordinary operating voltages. It

has become well known in the art to control the average output of anelectric valve, particularly a valve of the vapor electric dischar type,by controlling the phase relation etween the grid potential and theanode potential of the valve. By retarding the phase of the gridpotential of such a valve, the point in each positive half cycle ofanode potential at which the valve is rendered conducting issuccessively retarded and the average amount of energy transmitted bythe valve is correspondingly decreased.

It is an object of my invention to provide an improved electrictranslating circuit including electric valves in which the flow ofenergy from an alternating current supply circuit to a load circuit maybe controlled automatically in response to a predetermined electricalcondition of one of the circuits.

It is a further object of my invention to provide an improved electrictranslating circuit including electric valves for transmitting energyfrom an alternating current supply circuit to a load circuit in which anelectrical condition of the load circuit may be maintained constantautomatically by varying the phase relation between the grid 4. Electricvalve 1 may be of any of the 1881. Serial 80.630379.

and anode potentials of the valves in response to variations in theelectrical condition.

In accordance with one embodiment of my invention, I provide anarrangement for energizing a load circuit from an alternating currentcircuit through a pair of electric valves. In order to control theamount of energy transmitted by the electric valves I provide animpedance phase shifting circuit for varying the phase relation of therid potentials of the valves with respect to t eiranode potentials. Theimpedance of one of the elements of this phase shifting circuit isautomatically controlled in response to variations in a predeterminedelectrical condition of the translating circuit. For example, one of theelements of the impedance phase shifting circuit may comprise atransformer the secondary winding of which is short-circuited through asecond pair of electric valves. The impedance of this second pair ofelectric valves may be controlled by controlling their filamentexcitation in re sponse to a predetermined-electrical condition of thetranslating circuit, such for example as the voltage of the load circuitor the current flowing in either the alternating current supply circuitor the load circuit.

For a better understanding of my invention, together'with other andfurther objects thereof, reference is had to the accompanying drawing,taken in connection with the following description and its sco will bepointed out in the appended claims. The single figure of the accompanyindrawing illustrates my invention as appiied to an arrangement fortransmittin energy from an altern'ating current suppl y circuit to adirect current load circuit and for maintaining constant the averagevoltage of the direct current circuit.

Referring now to the drawing, there is illustrated an arrangement fortransmitting energy from an alternating current circuit 3 to a directcurrent load circuit 7. This arrangement includes an electric valve 1provided with a pair of anodes 2 upon which potentials areimpresscd fromthe alternating current source 3 through .a transformer several typeswell known in the art, but I prefer to use a valve of the vapor electricdischarge type. The secondary winding 5 of the transformer at isconnected at its ends to the anodes 2, and its midpoint 6 constitutesthe negative terminal of the load circuit 7 of which the positiveterminal is connected to the cathode-8 of electric valve 1. While I haveillustrated the electric valve 1 as a double anode, single cathodedevice and connected with the transformer 4 in fication, it will beobvious to those skilled in the art that two single anode valves may besubstituted therefor and that these-,valves may be reversely connectedin parallel if it is desired to supply anpalternating current loadcircuit, all -,without departing from iny invention.

Associated with each. anode 2 is a control electrode or grid9.to,'-which potentials are an inductance 15 and the; primary winding 16of a transformer '17; The inductive winding 14: is connected to thealterhating current source 3, and winding 13 ofgrid transformer 10 isconnected to an intermediate tap on the winding 14 and to thepointofgcom iection between inductance 15 and the primary wind ing 16 ofthe transformer 17.. 1

The transformer 17 is provided with a secondary winding 18 which isconnected at its extremities to tho anodes 19 of electric valves 20,which are preferably of the high vacuum pure electron discharge type. iThe electric valves 20 are respectively provided with filaments 21 whichare connected in series with each other and with a regulating resistor22 These filaments are shown as energized across the load circuit 7 butit will be obvious that they may be energized from any 'ciricuit in"proportion to the potential variations of 1 which it is desired tovarythe output of the apparatus. For example, thefilaments2l may beenergized from a shunt connected in series with the direct currentcircuit 7 or from a series transformer con n ectcd 1n the alternatingcurrent circuit 3, or from an inde-' pendent circuit-i A connection 23is made from the midpoint of secondary winding 18 of transformer 17 to apoint between filaments 21.

It is evident from t-hisconncction of the secondary winding 18,thattransformer l'l is open circu'itcd'as lon as filaments 21 re-' loadcircuit 7 .Wil-l-be aimaximum.

ture and that this transformer will carry a load current proportional tothe electron emission in the devices 20 as the filaments 21 becomeheated.

The winding 14, inductance 15 and primary winding 16 are so proportionedthat when the filaments 21 are'below the-electron "emitting temperature,and transformer 17 is therefore open circuited, the grids 9 receive,through-gridtransformer 1.0,a voltage .-which.is substanti allyin-pl1asewith the anode such a manner as to obtain full wave recti-f voltage. Theanodes will, under this condition, pass current: for the full normalperiod and the current output delivered to the On the other hand, if thevoltage of the load circuit tends to rise,due t'oa'decrease inload, orfor any other cau'se, the filaments-'21 are heated to a highertemperature. and the resulting electron emission permits current to fioWin winding 18. -The transformer 17 acts ;'as a non-inductive resistanceofa value dependent 'upon the; amount of electron emission. With anincr'ease in electron emission of the filaments 2 1,t-he efiective'resistance of the transformer '17 decreases andthe voltage impressedupon 'the g'rid transformer 10 is caused to lag behind the'anodevoltage,thus decreasing the current output of the apparatus, as will be wellunderstood by those skilled 'in'the art. Obviously, with ajdecrease involtage of the load circuit 7 the reverse opera- 'tion will take place.j

' jIn operation, the temperature of the filaments 21 is first adjustedby means of resistor 22 to obtain acurrent'flow through the elec- 'tricvalves20, corresponding to a predetermined voltage on the load circuit7'. Thereafter, any variation of the voltage in circuit 7 causes achange in the filament temperature and consequently change in theequivalent.

resistance oftransformer 17, accompanied by a shift in the phase of thegrid potential in the proper direction to return the output voltage ofthe apparatus to normal.

In case the filaments are not energized from the output circuit of therectifier 1 but from some other circuit, 'in proportion to the potentialvariati onsof which itisdesired to vary the .energy transmitted by theapparatus, it is the variation of the voltage in this other, circuit,to'which the filaments 21 are connectedfthat produces a variation in thephase relation of the the grid 9. e

=VVhile I have describedwhat I at present consider the preferredembodiment of my in potentials supplied to -vention,'it will be obviousto'those skilled in the art that various changes and modifications maybe made without departing from my invention, and I therefore aim in theappended claims to cover all such changes and modifications as fallwithin the true spirit and What I claim as new and desire to secure byLetters Patent of the United States, is:

1. In combination, an alternating current supply circuit, a loadcircuit, an electric valve provided with a control grid for transmittingenergy from said supply circuit to said load circuit, an impedance phaseshifting circuit comprising a plurality of impedance elements andassociated with said grid, a sec- 0nd electric valve for controlling theimpedance of one of said impedance elements, and means responsive to anelectrical condition of one of said supply and load circuits forcontrolling the conductivity of said sec- 0nd mentioned valve.

2. In combination, an alternating current supply circuit, a loadcircuit, an electric valve provided with a control grid for transmittingenergy from said supply circuit to said 10a circuit, an impedance phaseshifting circuit comprising a plurality of impedance elements andassociated with said grid, a second electric valve for controlling theimpedance of one of said impedance elements, said second 26 valve beingprovided with an electron emitting cathode, and means for exciting saidcathode in accordance with an electrical condition of one of said supplyand load circuits.

80 3. In combination, an alternating current supply circuit, a circuitsubject to electrical variations, and means for producing a potentialvariable in phase with respect to that of said supply circuit inaccordance with said electrical variations comprising a plurality ofimpedance elements connected across. said supply circuit for producingdephased potentials, one of said elements including an electric valveprovided with electron emitting cathode, and means for controlling theemission of said cathode in accordance withsaidelectrical variations.

4. In combination, an alternating current supply circuit, a circuitsubject to electrical variations, and means for producing a potentialvariable in phase with respect to that of said supply circuitinaccordance with said electrical variations including a reactor and animpedance device connected across said supply circuit for producingdephased potentials, said impedance device having sub stantially aresistance characteristic, means for controlling the impedance of saiddevice including an electric valve provided with a filamentary electronemitting cathode, and

means for energizing said cathode from said circuit subject toelectrical variations.

h In1 witness whereof I have hereunto set my an 60 DAVID C. PRINCE.

